Getting Around in Space

Obviously, it’s not easy to get around in space. There’s no air and everything’s a long ways away. This is why, for instance, we’re not living on Mars right now.*

One hopes that in the future we’ll find ways around these problems. And really, that future is closer than you might think. It’ll be awhile before we can travel to alien homeworlds at warp speed, but that’s most certainly not required to have relatively quick and most certainly interesting trips through space.

My novel will take place about 150 years in the future. I think this is the perfect time for near-future spaceflight, because it means that the technologies that you read about us having “someday” are thoroughly plausible. Gene therapy, mind-machine interface, and space colonies are all realities in the world of the early 2160s, but the most interesting to me right now is the propulsion technology they’ll have.

Obviously the chemical rockets that we use today will be hopelessly obsolete by then; they’ll have gone the way of the triplane and steam railroad. All three are essential “stepping stone” technologies, but there’s definitely not reason to use them once better alternatives are available.

In the case of my novel, the better alternative is the fusion rocket. Out of the many, many variants of nuclear propulsion that have been proposed, the fusion rocket has the best spread of advantages: high specific impulse, high jet power, and low radioactivity.

When I say fusion, I’m specifically referring to inertial confinement fusion, in which a tiny pellet of deuterium/helium-3 fuel is blasted with an ultra-high-energy laser or electron beam, which compresses and heats the mass until the fusion reaction begins. A magnetic field in the reaction chamber propels the resulting plasma out the rear of the spacecraft, thereby pushing the spacecraft forward. In theory, by feeding additional pellets into the fusion mass, you could initiate a self-sustaining reaction and thrust indefinitely. Using a system like this, scientists speculate, you could make round trips to Pluto in less than two years, and Mars in weeks.

That’s awesome, frankly, and it fits the requirements of my story perfectly. There’s no warp drive, no space fighters, and no artificial gravity, but at least you have a lot of ships able to easy move people and material through out the Solar System. Helium-3 from Jupiter powers ships moving iron, gold, and uranium from the asteroid belt to Venus, where the ships are built in the first place. That’s the kind of future I’m talking about.

Two other, minor comments. First is to remember the “Kzinti lesson,” so named in Larry Niven’s Known Space universe, which states, “a reaction drive’s efficiency as a weapon is in direct proportion to its efficiency as a drive.” If you light one of those suckers, it’ll fire a high-energy particle beam out the back of your ship that’ll fry anything it hits for tens of thousands of kilometers at least. So not so much useful for takeoffs, but if you’re taking off from somewhere you have plenty of other options.**

The second thing is that a ship propelled using ICF drives was actually proposed and designed (at least roughly) back in the 1970s. Designed by the British Interplanetary Society, it was called Project Daedalus and would have been at least theoretically possible to build in the designer’s lifetimes. It would’ve taken about 50 years to make a flyby of Bernard’s Star, thought back then to have at least one planet; the target nowadays would presumably the Gliese 581 system.

Next time (probably): I start to work on the following formula: character outlines(sub character plot arcs) plus rough plot outline equals detailed outline.

*Actually, the real reason is depressingly short-sighted politics in the mid to late 1970s, but the distance is a factor too. Also the no air.

** I highly recommend this series of books. They have been a profound influence on my own work.